Numerical study of the natural transition in hydrofoil boundary layers with superhydrophobic surfaces

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(2)

Published: Feb. 1, 2025

The natural transition of the boundary layer on a hydrofoil with superhydrophobic surfaces is investigated using numerical methods. A novel calculation approach featuring adapted vertical mesh basic laminar flows hydrofoils proposed and validated against experimental velocity profiles. eN method, corroborated by data, employed to predict locations layers. It observed that surface stabilizes layer, thereby delaying hydrofoil. As slip length increases, this delay effect becomes stronger. For surfaces, it consistently occurs location suction side takes place further downstream than its pressure side, aligning established principles regarding ordinary surfaces. new passive flow control strategy, different applied can be utilized achieve symmetrical characteristics asymmetric hydrofoils. Furthermore, transitional behaviors only one are discussed. found presence introduces distinct influences behavior opposing lacks such surface, which may attributed move in stagnation point located side.

Language: Английский

Physical characteristics of wall pressure fluctuations for fully developed turbulent annular channel flows

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(4)

Published: April 1, 2025

This study investigates the physical characteristics of wall pressure fluctuations for fully developed turbulent channel flows using large eddy simulation. Turbulent annular with three radius ratios (Rin/Rout = 0.33, 0.43, and 0.50) are numerically studied. Here, Rin Rout radii inner outer cylinders, respectively. A planar is set up to serve as a validation case, also representing specific condition Rin/Rout→1. The computational method carefully validated against previous direct numerical simulation data. On this basis, on walls compared. trend spectra consistent, while cylinder exhibits higher spectral magnitudes. Then, effects ratio As decreases, magnitude shows slight reduction at low wavenumbers frequencies, whereas wall, it increases significantly across entire range frequencies. suggests that convex curvature has mild effect structures streamwise spanwise length scales, concave sides impacts flow all scales.

Language: Английский

Boundary-layer transition on a shallowly submerged vehicle

Ocean Engineering, Journal Year: 2024, Volume and Issue: 317, P. 120051 - 120051

Published: Dec. 10, 2024

Language: Английский